import re

upper_char = unichr(0x1ea0) # Latin Capital Letter A with Dot Bellow
lower_char = unichr(0x1ea1) # Latin Small Letter A with Dot Bellow
    
p = re.compile(upper_char, re.I | re.U)
print p.match(lower_char)

p = re.compile(lower_char, re.I | re.U)
print p.match(upper_char)

p = re.compile('(?i)' + upper_char, re.U)
print p.match(lower_char)

p = re.compile('(?i)' + lower_char, re.U)
print p.match(upper_char)

p = re.compile('(?iu)' + upper_char)
print p.match(lower_char)

p = re.compile('(?iu)' + lower_char)
print p.match(upper_char)   # Error: got None